From the PARcore Data Visualization Studio Landing Page, navigate to this report by selecting the C-Item Change Analysis report icon.   This report is only applicable for requests that include the Analysis Type of Item Analysis - Differential Item Functioning, and had at least one DIF comparison with both a Before and After refinement conducted.  A request that did not have any refinement done will not qualify for this report. 

The bento box menu icon at the top left of the report can be used to navigate back to the Landing Page.
 




When first launching the report it will be empty.  Make initial filter selections in order to visualize the report.  Any filter with a red asterisk indicates it is required to have a selection made before the report can be displayed.


Filters
Refer to Visualize Results for general information about filter navigation for any report.  The filters for this report are:



 

• Analysis - select one analysis sequence number to view at a time.  The analysis sequence number will reflect the sequencing from Request Details for this request.
  • Upon first initializing this dashboard, the filter will display as "(Choose your analysis)" and a selection must be made. 
  • Select the search icon (magnifying glass) and enter search text to see Analysis filter options for the request you are viewing.  Using an asterisk in the search text box will display all possible analyses to choose from.  
  • Once the current analysis results have been reviewed, continue to use the search feature or utilize the slider arrows (< and >) to view each analysis one at a time.  If you only have one analysis to view, the slider arrows will be disabled.
  • The filter description will include the criterion score being analyzed as well as the reference and focal group.  Only one reference/focal group comparison will be displayed at a time.

• Item Scoring:  Users can select which set of items to view based on the item scoring (dichotomous and/or polytomous). 
  • Since dichotomous items and polytomous items display a different set of statistics, users will need to view one set of statistics at a time if  both dichotomous and polytomous items are included in the analysis.  
  • The default selection is "Dichotomous".  If the comparison being viewed contains only polytomous items or only polytomous items had C flags before refinement, the filter selection will display as "(Dichotomous)" and needs to be updated to select Polytomous before the table can be rendered.

• Use Code:  Users can select to filter the results to view only specific use codes if they desire.  
  • This is a multi-select filter.
  • Default filter selection:   (All)
  • The dropdown list is in alphabetical order and only includes use codes that are relevant for the items in the selected analysis and item scoring selected.  

• DIF Statistics:  Users can select which DIF statistics to display in the report table.
  • This is a multi-select filter.
  • A selection of relevant DIF statistics is already selected by default.  In order to view more or fewer statistics in the displayed table, adjust the filter selections and select APPLY.  Click out of the filter menu to close it.
  • The selection of DIF statistics differs between dichotomous items and polytomous items.

Example of dichotomous default selections                             Example of polytomous default selections

                                                    

• The only items included in this table are the ones that had a DIF Flag Category of C+ or C- before refinement was conducted.   The table will display all the relevant DIF statistics, based on your filter selections, for both the before refinement analysis and the after refinement analysis.
  • The assembly unit information is a concatenation of the assembly unit ID, test measure, and research usage type for that item.
  • If an accession number has more than one assembly unit and the "Combine Responses by Accession # Across Forms/AUs" procession option was selected, the statistics for that accession number will appear in the rows with the first assembly unit for that item.  The remaining assembly units for that item are displayed underneath for information purposes but do not have any statistics listed.

• If your selected analysis contains both dichotomous and polytomous items use the Item Scoring filter to review one set of results before changing the filter to view the remaining items.

• If your report includes more than one analysis or comparison, use the Analysis filter navigation to move from one analysis to the next as you complete your review(s).